Heat treating apparatus



K. MARSH 2,265,849

HEAT TREATING APPARATUS Dec. 9, 1941.

Filed Aug 2, 1940 6 Shets-Sheet 1 INVENTOR. K irI/and Harsh ATTORNEY.

Dec. 9, 1941. K. MARSH I HEAT TREATING APPARATUS Filed Aug. 2, 1940 6Sheets-Sheet 2 'INVENTOR. Kiri/and l'larsh BY WW Dec. 9, 1941. K. MARSHA HEAT TREATING APPARATUS Filed Aug. 2, 1940 6 sheets sheet 4 INVENTOR./f iri land Mars/I jBY Dec. 9', 1941. K. MARSH 2,265,849

HEAT TREATING APPARATUS Filed Aug. 2, 1940 G'Sheets-Sheet' 5 4 zao===s 1'i'ii'n V V III'IIIIIIIIIIIIIIIIII 1 INVENTCR. Kiri/and Marsh 6Sheets-Sheet 6 INVENTOR. Kiri/and Marsh ATTORNE Dec. 9, 1941. K. MARSHHEAT TREATING APPARATUS Filed Aug. 2, 1940 Ill Patented Dec. 9, 1941HEAT TREATING APPARATUS Kirtland Marsh, Pittsburgh, Pa., assignor toAluminum Company of America, Pittsburgh, Pa., a corporation ofPennsylvania Application August 2, 1940, Serial No. 349,676

(Cl. 26H) 16 Claims.

This invention relates to apparatus for heat treating metals and alloys.It pertains particularly to a system wherein apparatus is provided forhandling, heating, quenching, and drying of metal which is to besubjected to a heat treatment process. It further relatesto'combinations and sub-combinations of such apparatus.

The invention will be described with reference to the heat treatment ofmetal sheets of aluminum alloys though it is in no way confined thereto.Heat treating is defined for purposes of this invention as heating metalto a desired elevated temperature, holding the metal at that temperaturefor a prescribed length of time, and then rapidly quenching or coolingthe metal in a fluid coolant. metal, accurate temperature control anduniformity of temperature throughout the furnace heating chamber aredesired. Likewise, the ability to rapidly quench the metal after it hasbeen subjected to the required amount of heating, without excessive lossof heat from the heat-.

-ing chamber, is desired. The invention, therefore, contemplates theprovision of apparatus arquickly, and uniformly, and to quench theheated load of metal with great rapidity. While the apparatus of theinvention is particularly adapted to the performance of the abovedefined heat treating process, it will appear upon a reading of thisspecification that the invention may be useful in such other materialtreating processes as annealing, drying, baking, soaking, and preheatingof metal or other materials. In many of such processes apparatus of thecharacter here described and claimed may find utility.

Heat treating furnaces employed prior to this invention arecharacterized by numerous disadvantages. For instance, it has been knownto so position a furnace heating chamber and a load quenching tank as torequire that the load of metal be immersed in the water of the quenchingtank before it is moved into the heating chamber. Such an arrangement isundesirable because it requires additional input of heat to the load toevaporate the water clinging thereto af er it is drawn into the furnacechamber, and also because it results in a tendency for the, load to enon-uniformly heated. With some materals such as aluminum and its alloysthe presence of water on the surfaces of the metal being heated may evenresult in staining or marking of the metal, which is of courseundesirable, if not detrimental.

Prior efforts to construct a furnace arranged to In a furnace forheating the.

Noting the aforementioned disadvantages of A prior furnaces, the generalobject of this invention may be stated as the provision of a heattreating apparatus having a heating chamber spaced from a quenching tanka distance sulficient to permit supporting of a load therebetween, andhaving improved load handling apparatus associated therewith.

A further object of the invention is the provision of heat treatingapparatus adapted to dry charging of a load of metal and yet adapted torapid quenching thereof.

Another object is the provision of a tracksupported load carrier adaptedfor movement under a heating chamber and over a quenchin tank. It isalso an object to provide suitable load hoisting means for lifting aload carrier into a heating chamber and for lowering it into a quenchingtank.

80 Another object is the provision of a retractable (0 ticularly incombination with yieldable door sealload carrier track under a heatingchamber arranged to permit the lifting of a load of material into aheating chamber and lowering thereof into a quenching tank.

Another object is the provision ofa slidable door for a bottom openingof a heating chamber. It is also "an object to provide door traversingmeans adapted to withdraw a door from under a heating chamber, and toreturn the same, paring means,

Another'object is the provision of a track-sup- I ported slldable doorfor the bottom of a heating chamber adapted to be traversed lengthwiseof 4 the heating chamber to permit entry and removal heat treatingapparatus.

ing, drying, and unloading of one or more loads of metal.

The invention also has: for an object the cooperative inter-relation ofsome or all of the aforementioned devices. It is particularly an objectto provide a retractable load carrying track and a slidably removabledoor under the heating chamber of a heat treating apparatus having aquenching tank spaced therebelow a distance greater than the verticalheight of a furnace load.

These and other objects will be appreciated more fully upon a reading ofthe following description of a preferred form of heat treating apparatusembodying the invention. The objects are to be taken either singly or incombination, and are to include such other advantages as are explainedherein but not above particularly expressed.

In the drawings cation:

Fig. 1 is a plan view of the heat treating apparatus constituting thepreferred embodiment of the invention, showing the load handling means,the heating chamber, the drying chamber, and other parts thereof;

Fig. 2 is a side elevation of the apparatus of Fig. 1 (to the samescale), showing in addition thereto the quenching tank and other partsthereof; 7

Fig. 3 is an enlarged plan view taken on the line IIIIII of Fig. "I andshowing the heating forming part of this specifisuch loads may besupported on a load carrier in parallel spaced relation, the spacingbetween v sheets being preferably at least 1% inches from center tocenter. The above load specifications are setv forth merely as exemplaryof the purposes to which the invention may be applied.

The preferred apparatus may be generally identified as an elevator typeof furnace with a quenching tank directly under a heating chamher, butwith sufllcient vertical height between the bottom of the heatingchamber and the top of the quenching tank, at floor level, to permit aload of material of the character above described to be movedtherebetween on an overhead roller track. One or more load carriers maybe' employed with this apparatus to support loads of sheets of thecharacter above dechamber and part of the load handling means showngenerally in Fig. 1, a portion of the heating chamber .and hoistingmeans thereon being broken away to illustrate apparatus associatedtherewith;

Fig. 4 is a side elevation, with parts broken away, of that portion ofthe apparatus shown in Fig. 3 (to the same enlarged scale), showing inaddition thereto the quenching tank and other parts thereof;

Fig. 5 is a plan of the door traverse mechanism, part of the loadhandling means, and part of the drying chamber shown generally in Fig. 1(to the same enlarged scale), a portion of the I door being broken awayto illustrate other parts of the apparatus;

Fig. 6 is a side elevation of that portion of the apparatus shown inFig. 5 (to the same enlarged scale);

Fig. '7 is a vertical section taken on line VIIVII of Fig. 3 and showingthe heating chamber, bottom door therefor, load handling means, andquenching tank (to the same enlarged scale), the door being shown insealed and unsealed positions on opposite sides of the center line;

Fig. 8 is an enlarged detail and sectional view door sealing means,taken along the line XI-Xf of Fig. 8.

The furnace apparatus shown in the drawings was designed for the heattreatment of 6,000 pound loads of aluminum alloy sheet or plate made upof as many as 36 sheets, each 28 feet scribed, and a suitable track ispreferably provided for movably supporting a load carrier under theheating chamber and for conveying a load carrier beyond the heatingchamber to a drying chamber and back to a reloading-position. Theapparatus is preferably provided with suitable load hoisting means forlifting a load carrier and load supported dependingly therefrom into theheating chamber, lowering it into the quenching tank, and again raisingit to the track under the heating chamber. A slidably removable door ispreferably provided at the bottom of the heating chamber, with suitablemechanisms for opening and closing the same. The track for supportingthe load carrier under the heating chamber is preferably maderetractable to permit free passage of a load carrier into the heatingchamber and into the quenching tank. Turning now to the drawings,particularly to Figs. 1 and 2 thereof, the preferred form of heattreating apparatus will now be described.

Loading transfer To the left in Figs. 1 and 2 there is shown a loadingtransfer I manually or otherwise laterally movable on two transfer rails2 between a position in alignment with a return load carrier track madeup of rollers l (as in Fig. 1) and a position in alignment with afurnace heating chamber 5. This loading transfer I preferably consistsof a frame fabricated from structural shapes and having longitudinalside members tied together by suitable lateral members. The loadingtransfer I is dependingly supported from the two transfer rails 2 bymeans. of overhead transfer rollers 0 at each corner thereof, the rails2 being supported from the floor at-their ends by structural, railsupporting columns I.

, The longitudinal side members of loading transfer I each carry alongitudinally extending series of inwardlypresented track rollers lwhich form a load carrier track serving as an extension of the returnload carrier track, above generally referred to. when inalignmenttherewith.

The track rollers I of loading transfer I are arranged for the supportand e thereover of a load carrier ll (see also Figs. 3 and 4) which.consists of a frame similar in character to the frame of transfer I. Itis made up of longitudinal side members tied together at their ends andat intermediate points with suitable lateral members. The longitudinalside members of load carrier l0 are shouldered as at ll (see Fig. 4) tofit the track made up of rollers I. Thus, load carrier Ill, throughshouldered portions II, is adapted to ride on the track rollers 8 of thetransfer I.

long and inches wide. The sheets forming It will be noted that loadcarrier II is proof. The eyes I2 are adapted to be engaged by suitableattaching means, associated with hoisting apparatus, for lifting of theload carrier III into the heating chamber 5 and lowering there of into aquenching tank I5 under chamber 5. Supported dependingly from loadcarrier I6 are a plurality of load hangers I3 arranged in a plurality oflongitudinal rows and attached to Iongitudinal structural members (notshown) forming part of the load carrier I 0. Each hanger I3 comprises adepending rod, cable, or wire and a suitable clip, clamp, or wedginggripper adapted to engage the upper edge of a metal sheet or plate. Thedetails of the hangers I3 are not here important since any of variousknown devices of this character may be employed for attaching the metalsheets to be heat treated to the load carrier II). By arranging hangersI3 in longitudinal rows a plurality of metal sheets may be hung from theload carrier II) in parallel spaced relation. A large'number of hangersI3 is employed to securely and uniformly support each sheet forming partof the load, since it is desirable to prevent sagging of the sheetsduring heat treatment and to keep one sheet from touching another as faras practicable.

In the practice of the invention a load carrier I0 is loaded with aplurality of sheets, by securing the same to hangers- I3, when theloading portions of a load carrier track comprised of retractable trackrollers I4 under heating chamher 5 and delivery track rollers I6, thelatter being supported by structural members I'I extending beyond theend of the heating chamber 5 opposite to loading transfer I. It willappear then that a load carrier III may be manually or otherwise movedfrom the loading transfer I onto the retractable track rollers I4, underthe heating chamber 5.

Furnace apparatus heating chamber 5. The retractable rollers I4 andapparatus thereabove are located above'the floor level sumciently forthe passage of a load to charging. position, the quenching tank I5 beingdirectly below the heating chamber 5 but depressed below the floorlevel.

The heating chamber 5 is provided with door 20 for the receipt anddischarge of the load through the bottom thereof, door 20 beingremovable from under the heating chamber 5 by horizontal slidingmovement to the right, as

. viewed in Figs. 1. and 2, where it is shownin open position. Forsupporting the door during opening and closing movements, there isprovided'a door track 23 formed of angles at either longitudinal side ofheating chamber 5 and extending beyond the same at one end as abovedescribed.

An operating cylinder 2| and mechanism associated therewith, which willbe described later, are employed for effecting the movement of door 20on tracks 23. provided on each side of heating chamber 5 for actuating adoor locking means, which will also be later described, adapted to sealthe door against the bottom of the heating chamber 5. The aforementionedangles forming track23 support the door 26 during its horizontalmovement at positions above a load carrier III and track rollers I4 andI6 for supporting a load carrier III.

The retractable track rollers I4 are mounted on two longitudinallyextending structural members 25 (see Fig. 3), each of which isretractable to the side of the heating chamber 5 through the actuationof an operating cylinder 26 and mechanism associated therewith. Thismechanism, to be later described in detail, is arranged to move thestructural members 25 into and out of projected operative position. Fig.3 shows structural members 25, carrying track rollers I4 in projectedposition.

As aforementioned, the quenching tank I5 is located beneath the floorlevel and below the heating chamber 5. It is of conventionalconstruction and deep enough to accommodate a full load of maximum sizesheets along with a load carrier I0 which supports the same (as in Figs.2 and 4). The usual spill drain 28 is provided at the upper portion ofthe quenching tank I5.

The heating chamber 5 is preferably heated by electric resistanceheaters in conventional fashion. Surmounting the chamber 5 are sixfurnace blowers 29 for the forced circulation of the furnace atmosphere.heating and circulating the furnace atmosphere are not important to thepresent invention, and will not be further described. Also, surmountingthe heating chamber 5 there is provided a hoist frame 30 supporting aload hoist mechanism.

The hoist mechanism comprises eight hoisting cables 3| passingdownwardly through the roof of the heating chamber 5 to a pair ofinterto the top of hoist frame 36. They each pass I around two pulleys34 and 35, the fixed pulleys '35" being suitably mounted on the base ofhoist frame 36. The movable pulleys 34 are mounted on a movable carriage36 sothat they may be moved to the left or right (as viewed in Figs. 2and 4) to, in effect, shorten or lengthen the hoisting cables 3I.Carriage 36 is a fabricated structure supported by rollers 43 at thesides thereof (see Fig. 3) adapted to ride in guide rails 4| mounted onhoist frame 30. Forward position of carriage 36 is limited by a stop 42(see Fig. 4), and rearward position thereof is limited by the upwardposition of load lift beam 32 in heating chamber 5, or by the stroke ofthe hoist operating cylinder 38. The carriage 36 is secured to thepiston rod 31 of operating cylinder 36, by

actuation of which the load lift beam 32 may be raised or lowered as isdesired. in a known manner. Associated with the piston rod 31 andcylinder 38 there is provided a latch 39 to lock the hoisting apparatuswhen the load is within the heating chamber 5 so as to preventaccidental release thereof before retractable rollers I4 are retracted.The details of this latch 39 are not An operating cylinder 22 is Thedetails of apparatus for a essential to the invention, and will not befurther described.

At the lower extremities of the hoist cables 3I on either side of theheating chamber 5 are secured, through suitable connecting links, thetwo longitudinally extending portions of the load lift beam 32 which maybe, as is shown in Fig. 4, made up of a plurality of hingedly relatedbeam sections disposed on opposite interior sides of the heating chamber5, tied together by suitable cross members. The load lift beam 32 is, ineffect, one simple frame but is constructed for slight hinged relationof the aforementioned sections to make it more easily attached to theload carrier III, and to allow for variable heat expansion thereof.Depending from the load lift beam 32 along each longitudinal sideportion thereof are a plurality of hooks 48 adapted to be engaged withthe eyes I2 on a load carrier III. A load carrier I8 is engaged with theload lift beam 32 by moving the load carrier on track rollers I4 a fewinches beyond registering position with the load lift beam, thenlowering the load lift beam. so

that the hooks 40 are opposite the eyes I2, and then slightly moving theload carrier to place the eyes I2 over the hooks 40. Thereupon, the loadlift beam 32 may be raised by the hoisting mechanism, actuated by theoperating cylinder 38, to lift the load carrier I and load supportedthereby. In this manner the load carrier I0 may be removed from itssupport on retractable track rollers I4. When it is desired tore-deposit the load carrier III upon the rollers I4, and dis engage theload lift beam 32 from the load carrier III, the reverse of the abovedescribed procedure may be employed.

Drying apparatus Leaving for later discussion further details of theapparatus associated with the heating chamber and quenching tank- I5, itis pointed out that a load carrier III will be removed from under theheating chamber 5 by passage along the retractable track rollers I4 overonto the delivery .track rollers I5. The load will be moved furberscarrying the inwardly presented track rollers 45. It is dependinglysupported by overhead transfer rollers 41 on three transfer rails 48 formovement'from a position in alignment with the track formed by rollersI8 to a position in alignment with the aforementioned return trackrollers 4. The transfer rails 48 are supported by suitable structuralrail supporting columns 44. The lateral transferring motion of dryingtransfer 45 may be imparted manually or by suitable mechanical means.Further associated with the drying transfer 45 is a U-shaped enclosingshell, having a partial top and no bottom, and having an open end forreceipt and delivery of the load. The loading transfer, midway of itsmotion between the position in alignment with the track rollers I8 andthe position in alignment with track rollers 4, is adapted to be stoppedand located under a drying apparatus 58 mounted on transfer rails 48, sothat the drying apparatus 58 and transfer 45, in cooperation with thefloor, form a. drying chamber open only, if desired, at the left end (asviewed in Figs. 1

aperture 43 is provided in the partial top of dryapparatus 58. Thedrying apparatus 50 comprises suitably arranged blowers 5| adapted toblow air through electric or steam heaters, and through. aperture 48into drying transfer 45, to circulate heated air through the load forevaporating the quench water therefrom.

On completion of the drying operation a load carrier III on dryingtransfer 45 is adapted to be placed in alignment with return trackrollers 4 and delivered therealong over to the loading transfer I. Thereturn track rollers 4 form a return load carrier track, the rollers 4being mounted in structural members 54, supported from the floor bystructural columns 55. Thus, it will be seen that the loading transferI, track made up of rollers I4 and I5, drying transfer 46, and returntrack made up of rollers 4 provide a load circulating track systemcapable of accommodating 'several load carriers I8. Load carriers areshown in various positions in the drawings for clarity in description.The load carriers may be unloaded and reloaded at any desired positionalong this track system. The preferred loading position is at theloading transfer I, and the preferred unloading positions are alongreturn track rollers 4.

Retractable track The retractable track will now beparticularlydescribed with reference to Figs. 3, 4, '7, 8, and 10.Description of the retractable track made up of rollers I4 andstructural members 25 will be confined to that portion thereof locatedon one side of the heating chamber 5, which will exemplify the operationof the retractable track as a whole. It will be noted that the trackrollers I4 are pin supported in longitudinally-extending structuralmembers 25, being secured thereto by nuts 24 (see Figs. 8 and 10). Thestructural members 25 extend throughout the length of the heatingchamber 5 and are secured by T connections to horizontally disposed rackmembers 50, perpendicular thereto. The rack members 58 are fabricatedstructural members made up of two back-to-back channels having securedtherebetween, by bolts 51, and facing downwardly, a rack portion 5|.Each rack member 50 is supported indirectly by structural heatingchamber columns I8 through the medium of a pair of lower fulcrum rollers52 and a pair of upper fulcrum rollers 58. The rollers 52 are placedover a pin 53 mounted in a bracket secured by bolts 55 on an angle 55connecting interiorly with and across the structural columns I8. Theselower fulcrum rollers 82 support the rack member 58 on the side of thestructural columns I8 facing the interior of the heating chamber 5.Similar upper fulcrum rollers 58 are placed over a pin 59 mounted in abracket 18 secured by bolts 12 on an angle 'II- connecting exteriorlywith and across the structural columns I8. They support the outer end ofeach rack member 58 I8. The cylinder 25 has a piston rod 13 suitably and2). An

connected to a rack I4 in engagement with a pinion I5. The pinion I5 ismounted on a shaft I8 extending the length of the heating chamber 5.Shaft ,18 is supported in bearing brackets 'I'I secured by bolts 82 onan angle 18 connecting structural columns I8. The rack 14 is heldagainst the pinion 15 by a suitable backing roller I8 opposite theretosuitably mounted and supported. Operation of the piston rod I3 causesthe rack 14 to impart rotary movement through the pinion I to the shaft18. Spaced opposite each rack member 88 is a suitably keyed pinion 88 onshaft 16 which engages the rack portion 8| of each rack member 88. Thus,rotation of shaft I8 imparts rotation to pinions 88 and thereby efiectsinward and outward movement of each rack member 88. Two cylinders 28,one at each side of the furnace, through the aforementioned linkages,are efiective to commonly actuate all of the rack members 68 so as toproject or retract the retractable track formed by rollers I4 at thedesired times. The mechanism here described is duplicated on both sidesof the furnace apparatus, and thus, the simultaneous operation orsubstantially simultaneous operation of two operating cylinders 28 iseffective to project the rollers I4 so as to form a load carrier track,or to retract the same for the vertical raising or lowering therebetweenof the load carrier I8 and load supported thereby.

Door operating mechanisms 30 members forming a hollow frame that isfilled with suitable insulating material, and is adapted for closing offthe opening in the bottom of the heating chamber 5 and sealing the same.To effect the sealing action a-suitable gasket'l8 is provided around theupper edges of'door 28 so 40 that sealing pressure on the bottom of thedoor 28 may yieldably sealthe door 28 against, the bottom of the heatingchamber 5. The longitudinal sides of the door 28' are provided withshouldered recesses 85 (see Fig. 8) containing yieldably mounted springholders 88. Each spring holder 88 is pivotally secured on a pin 88 to abracket 81. (see Fig. 11) attached to the door 28 in one of the twoshouldered recesses 85. Each spring holder 88, at the other end thereof,is provided witlna cylindrical socket 88 adapted to receive anadjustably compressible spring 88. The spring is held in socket 88 bymeans of a bolt 8| passing through the lower end of socket 88 and by awasher 82 and nut 88 at the top thereof, these means being arranged toconfine the spring between the washer 82 and the bottom of socket 88.The upper end of bolt 8| is adapted to bear against a recess 88- of door28. The socket 88 of each spring holder 88 is provided with a lug or ear88 through which a bolt 85 loosely passes. The bolt 85 is carried by thedoor frame and has adjusting nut 81 and locking nut 88, whereby thespring holder 88 may be adjustably positioned with respect to the door05 frame. When the spring holders are moved upwardly, the spring pressedbolts 8| engage the bottom of the door frame, and the door 28 is raisedthereby to sealing position under a pres sure determined by the pressureof the springs 88. The length and load of each spring 88 may be suitablyadjusted by tightening or loosening the nut 88 on bolt 8I. Thus, it willappear that pressure upwardly exerted on each spring holder 88 will beadapted to yieldably and releasably 7 seal door 28 and gasket l8 againstthe bottom of heating chamber 8.

As aforementioned, there are a plurality of spring holders 86 secured,as above described, along the shouldered recesses on either side of door28. A plurality of roller clamps I88 are adapted to press against thespring holders 88 to raise the door 28 into sealing position. Theseroller clamps I88 take the form of cranks, secured to stub shafts I8lthat extend crosswise of the furnace from immediately under thelongitudinal edges of the door 28 to the outside of the frame work ofthe apparatus. The roller clamps I88 extend normally parallel to springholders 88 and are provided with pin supported clamping rollers I82adaptedto bear against the spring holders 88. The shafts I8I are mountedin suitable bearings in brackets I88 dependingly supportedfrom doortrack angles 23 and angles 'II above mentioned.

' On the outer end of each shaft I8I there is secured a crank lever I84.Each of the crank levers I84, along the length of each side of thefurnace,- is connected by suitable clevis and pin. The opera" connectionto an operating rod I85. ating rods I85, at the end of the heatingchamber 5 adjacent the loading transfer I, are connected by links I 88to bell cranks I8'I rotatably mounted on pins supported in brackets I88(see Fig. 3) secured to structural columns 'I'8. The other ends of bellcranks I8'I are secured to piston rods I88 of the operating cylinders22.

Thus, it will appear that motion of a piston rod I88 will impart rotarymovement to a bell crank I81 which, through a link I88, will move 'anoperating rod I85 lengthwise of the heating 45 the door 28. The springs88 are adapted to permit the necessary amount of overtravel inherent inthe use of a plurality of commonly actuated roller clamps I88, andfurthermore, by their adjustability are adapted to exert a predeterminedsealing pressure on the door 28. The

pressure exerted by each roller clamp I88 on the door 28 through eachspr ng holder 88 will be determined by the amount of precompression ofeach spring 88 attained through the adjustment of each nut 88.

What has been just described is the actuating mechanism for verticallymoving the door into and out of sealing position. In its lower openposition, the door is supported on the heretofore mentioned track 28' bymeans of a series of rollersll8 disposed along each lateral edge of thedoor, as best seen in Figs. 7 and 8. The track rails 23 are secured tothe lower flanges of channels III that are secured to the under side ofthe furnace structure. The door also is provided with guide rollers II8that are joumalled on vertical axes for engagement with the webs of thechannels III during travel of the door on the track 28.

Referring now in particular to Figs. 5 and 6, the mechanism which may beemployed for removing the door 28 from beneath the heating chamber 8 andreturning the same will be described. The door 28 is arranged to betraversed on the track 28 beneath the heating chamber 8 a direction.

over onto an extension of track 23 formed by similar anglessupported'upon structural members II4, which portion of track 23 extendsbeyond the heating chamber on the end opposite to the loading transferI. In these figures, the door is shown so removed from under the heatingchamber 5 and resting upon the extended track 23.

The traversing longitudinal movement of door 20 between its positionunder the heating chamber 5 and the position shown in Figs. 5 and 6 iseffected by means of pairs of traversing cables I I5 and I I5a,respectively, passed over pulleys I I6 secured to the base of heatingchamber 5 and over pulleys II'I secured to cross pieces II8 mounted upontransfer rails 48 adjacent the drying apparatus 50. Each end of theupper strands of cables H5 and II5a is secured in multiple wraps overone of four driving drums or pulleys H9, the wrappings of the respectivepairs of cables on their drums "II! being effected in oppositedirections. Each end of the lower strands of cables I I5 and I I5a issecured, through a suitable adjustable anchor connection I20 to abracket extension I22 of the door 20 provided at the end thereof nearestthe drying apparatus 50. Thus, it will appear that rotation of thedriving drums I I9 in one direction will efl'ect winding of the cablesof one pair and unwinding of the cables of the other pair upon theirrespective drums. whereby the door is moved longitudinally in oneRotation of the drums in the opposite direction will effect travel ofthe door in the opposite direction.

The driving pulleys II! are suitably keyed to a common shaft I24 mountedin bearing brackets I25. mounted on cross members I21 supported by theaforementioned structural columns II4. A pair of channels I25, likewisesupported on cross members I21, supports the operating cylinder 2I. Thiscylinder is disposed with its axis parallel to the longitudinaldirection of motion of the door 20 and has a piston rod I30 secured to arack I3I, the latter meshing with a pinion I34 mounted centrally of theshaft I24. For holdin the rack I3I against the pinion I34 an overheadbacking or guide roller I35 is provided opposite the pinion I34, whichguide roller I35 is secured in suitable retaining members I35. The endof the rack I3I is provided with a supporting roller I30 adapted to rideon a rail I39 mounted at one end on a beam I26 and extending over to across member I40 supported adjacent the drying apparatus 50. Crossmember 0' is mounted on cross pieces II8 bridging transfer rails 43.From the foregoing description, it will appear that motion of the rackI3I imparted by operating pressure from cylinder 2I may be employed forrotating drive pulleys Ill and traversing the door 20 to and from itsposition beneath the heating chamber 5.

Operation The preferred mode ofoperation of the heat treating apparatusherein described may be most Brackets I25 are secured to beams I25paratus, as shown in Fig. I, and that there is a load of material inunloading position supported crating cylinder from a third load carrierI0 on the return track formed by rollers 4.

The load carrier I0 on loading transfer I will be in the process ofbeing loaded with sheets to be heat treated, these sheets being securedto the load hangers I3 depending from the load carrier I0. Likewise,at-the same time, the load carrier I0 which is in unloading position onthe return track may be in the process of being unloaded by removal ofthe metal sheets from the load hangers I3, which support the same. Theseloading and unloading operations will take place during the period ofheat treatment including heating and quenching, if desired, of stillanother load in the furnace heating chamber 5 or in the quenching tankI5. Thus, a new load of material will be ready for entry into theheating chamber 5 as soon as the preceding load is removed from thefurnace or the quenching tank, and an unloaded carrier I0 will be readyto be loaded immediately following the loading operation on the previousload carrier I0.

It is further assumed that the furnace door 20 is under the heatingchamber 5 and sealed thereagainst. After the load in the heating chamber5 has been raised to a heat treating temperature and retained at suchtemperature for the desired length of time, the following steps will becarried out. The retractable rollers I4 beneath the heating chamber 5will be retracted to the sides of the heating chamber 5 by the operationof the operating cylinders 25 associated therewith. When the load trackformed by retractable rollers I4 has been retracted, the door 20 will bemoved to unseal thesame from the heating chamber 5. To perform thisoperation, the operating cylinder 22 will be actuated to release andlower the door sealing roller clamps I00. 'Release of the roller clampsI00 will permit the door 20 to move downward until its rollers IIOengage the door track 23. 'Thereupon, the door 20 will be withdrawn frombeneath the heating chamber 5 by actuation of the operating cylinder 2I,exerting a pulling force through the traversing-cables II5a. Thus, thedoor will be released and removed from beneath the heating The load liftbeam 32 i adapted to support the load carrier I0 and load dependinglyhung therefrom in the quenching tank I5 for the desired quenchingperiod. In cases where it may be desirable to do so, the load lift beam32 may be disengaged from the load carrier I0 when it is in, orimmediately above, the quenching tank I5. However, this is not thepreferred cycle of operations. Such deviation from the preferred cycleof operations would probably require the provision of a load carrierrest in the quenching tank similar to the retractable rollers I4 adaptedto support the load carrier I0 between the heating chamber 5 and thequenching tank I5.

When it is desired to raise the load out of the quenching, tank I5, thehoisting cables II will again be raised by the operation of the op- 33.The lifting operation undertaken by the hoisting cables 3| will bediscontinued when the load carrier I is disposed slightly above thelevel of the retractable rollers I4. Thereupon, the retractable rollersI will be projected into their inward positions by the operation ofoperating cylinder 26, so that the rollers M will be in position underthe load carrier Hi to support the same. Thereupon, the load carrier Iwill be deposited upon the retractable rollers M by slight lowering ofthe hoisting cables 3| through actuation of the operating cylinder 38.Following the depositing of the load carrier 10 on the retractablerollers M, the hoisting cables will preferably be lowered a little so asto permit disengagement of the hooks 40 on load lift beam 32'from theeyes [2 of the load carrier I0. Thereupon, disengagement of hooks 40 andeyes 12 will be effected by slight horizontal motion of the load carrierID with reference to the loadlift beam 32. Upon disengagement of theload lift beam 32 from the load carrier II), as described, the load liftbeam 32 will preferably be raised slightly above the load carrier It soas to permit the free passage of load carrier l0 over the rollers l4 andbeyond the heating chamber 5 onto the rollers l6 forming a deliverytrack. The load will be moved over to the rollers l6 manually or bysuitable-mechanical devices.

If it is desired, the load lift beam 32 may be fully retracted withinthe heating chamber 5 to permit closing of the heating chamber bytraversing the door 20 thereunder and sealing the same thereagainst.This may be desirable if there is to be appreciable time between theremoval of one load and the insertion of another load.

As soon as the load, which has been above described, has been moved overonto rollers IS, the new load which has been secured to the load carrierII) on loading transfer I will be moved from the loading transfer I ontothe retractable rollers l4 under the heating chamber 5. If the door 20has been closed, it will be opened to permit receipt of the newly placedload carrier I0. Assuming the door to be open,- the load carrier IIIwill be raised into the heating chamber 5 upon the performance of thefollowing operations. The load lift beam will be lowered,throughoperation of the hoisting cables 3| and operating cylinder 38, sothat the hooks 40 are again opposite eyes l2 of the load carrier Ill.Thereupon, the load carrier ID will be engaged with the hooks of theload lift beam 32, and the load lift beam 32 and loadcarrier III will beraised into .the heating chamber 5,through op- Upon the sealing of thedoor 20, the heating portion of the heat treating process will beinstituted, and upon its completion, the cycle of operations which hasbeen hereinabove described will be again carried out with reference tothe load within the heating chamber 5. At this time, the load carrierl0, which has been in unloading position on the delivery track 4, willbe delivered onto the loading transfer I and there loaded.

The load carrier which was moved out onto delivery rollers IG will bepreferably immediately moved onto the rollers 45 of the drying transfer.

drying transfer 46 will preferably be moved laterally into alignmentwith the return track rollers 4. Thereupon, the load carrier III will beconvenient loading and unloading of material to be subjected to a heattreating process, and that it permits rapid entry of the material intothe heating chamber and rapid delivery of the material from theheatingchamber to the quenching tank. It will further appear that itpresents an organization of apparatus particularly well adapted to thedry charging of a load into the heating chamber and to the rapidquenching thereof, as well as to the-rapid removal and dispositionthereof both in a drying chamber and to an unloading P sition, and thatthe several operations of the entire system can be carried outsubstantially concurrently.

While the invention has been described with reference to itsadaptability to handle loads of metal to be heat treated, particularlyloads made up of metal sheets, it will appear that it is adapted to thehandling of other types of loads, and that the apparatus may be usefulin the performance of other metal treating processes, or to theperformance of processes on other materials.

Numerous modifications may be made in the mechanical structure of theapparatus described.

eration of the operatingcylinder 38 and hoisting cables 3|. The liftingof the load into the heating chamber may be temporarily interruptedafter partial lifting of the load carrier lfl-to permit retraction ofretractable'rollers It in order to prevent any interference of the loadthereof with load carrier l0 and its load as it passes into the loadchamber 5. The retraction of the rollers 14 at this time, it is noted,does away with the necessity of retracting the same when it is desiredto lower the load-from the heating chamber 5 into the quenching tank l5.

When the load lift beam 32 has been raised to carry the load carrier l0into proper position within the heating chamber 5, the door- 20 will betraversed under the heating chamber 5 by operation of the operatingcylinder 2|. It will then be raised into sealing position by theoperation of the operating cylinders 22, as above described.

paratus have been only generally referred to since their design willbecome apparent to those skilled in the art upon the reading of thisspeci- Y flcation. The invention is therefore set forth in the appendedclaims with the intent that they be read broadly in the light of theobjects of this invention, and with only such limitations as are imposedby the prior art. f

What is claimed is:

1. In combination with a furnace having a heating chamber, a bottom doorfor said cham-; her, a tank located below said chamber a distancegreater than the load height thereof, means for supporting a furnaceload between said chamber and said tank, said load supporting meansbeing retractable from supporting positron, and means for liftingafurnace load from said load supporting means into said chamber, saidlifting means being adapted to lower the lifted load into said tank whensaid load supporting means are retracted. I

zontal delivery therealong of a furnace load, said load supporting trackbeing retractable toward at least one side of said chamber, and meansfor lifting a 'furnace load from said load supporting track into saidchamber, said lifting means being adapted to lower the lifted load intosaid tank when said load supporting track is retracted.

3. In combination with a furnace having a heating chamber, a bottom doorfor said chamber, a tank located below said chamber a distance greaterthan the load height thereof, a load supporting track beneath said doorfor horizontal delivery therealong of a furnace load, said loadsupporting track being retractable toward at least one side of saidchamber, hoist means for raising, lowering, and holding a furnace loadbetween and at positions in said chamber, in said movable door adaptedto be upwardly sealed against the bottom of said chamber, yieldablemeans for releasably pressing said door into sealing position, meansbeneath said chamber and extending beyond at least one end thereof forsupporting said door for horizontal opening and closing movement whenreleased, means for moving said door along said door supporting tank,and on said load supporting track, and 1 means for retracting said loadsupporting track to permit raising or lowering of a furnace load and forprojecting the same to receive and support a furnace load.

4. In combination with a furnace having a heating chamber, ahorizontally movable bottom door for said chamber, means for opening andclosing said door by sliding movement, a tank located below said chambera distance greater than the load height thereof, means for supporting afurnace load between said chamber and said tank, said load supportingmeans being retractable from supporting position, and means for liftinga furnace load from said load supporting means into said chamber, saidlifting means being adapted to lower the lifted load into said tank whensaid load supporting means are retracted.

5. In combination with a furnace having a heating chamber, ahorizontally movable bottom door for said chamber, means for opening andclosing said door by sliding movement, a tank located below said.chamber a distance greater than the load height thereof, a loadsupporting track beneath said door for horizontal delivery therealong ofafurnace load, said load supporting track being retractable toward atleast one side of said chamber, and means for lifting a furnace loadfrom said load supporting track into said chamber, said lifting meansbeing adapted to lower the lifted load into said tank when said loadsupporting track is retracted.

6. In combination with a furnace having a heating chamber, ahorizontally movable bottom door for said chamber, means for opening andclosing said door by sliding-movement, a tank located below said chambera distance greater than the load height thereof, a load supporting trackbeneath said'door for horizontal delivery therealong of a furnace load,said load supporting track being retractable toward at least one side ofsaid chamber, hoist means for raising, lowering, and holding a furnaceload between ing beyond at least one end thereof for support-- a ingsaid door for horizontal opening and closing means, a quenching tanklocated below said chamber a distance greater than the load heightthereof, means for supporting a furnace load between said chamber andsaid tank, said load 'supporting means being retractable from supportingposition, and means for lifting a furnace load from said load supportingmeans into 'said chamber, said lifting means being adapted to lower thelifted load into said tank when said load supporting means areretracted.

8. In combination with a heat treating furnace having a heating chamber,a horizontally movable door adapted to be upwardly sealed against thebottom of said chamber, yieldable means for releasably pressing saiddoor into sealing position, means beneath said chamber and extendingbeyond at least one end thereof for supporting said door for horizontalopening and closing movement when released, means for moving said .dooralong said door supporting means, a quenching tank located below saidchamber a distance greater than the load height thereof, a loadsupporting track beneath said door for horizontal delivery therealong ofa furnace load, said load supporting track being retractable toward atleast one side of said chamber, and means for lifting a furnace loadfrom said load supporting track into said chamber, said lifting meansbeing adapted to lower the lifted load into said tank when said load supporting track is retracted.

9. In combination with a heat treating furnace having a' heatingchamber, a horizontally movable door adapted to be upwardly sealedagainst the bottom of said chamber, yieldable means for releasablypressing said door into sealing position, means beneath said chamber andextendmovement when released, means for moving said door along said doorsupporting means, a'

quenching -tank located below said chamber a distance greater than theload height thereof, a

- load supporting track beneath said door for horiand at positions insaid chamber, in said tank,

zontal delivery therealong of a furnace load, said load supporting trackbeing retractable toward at least one side of said chamber, hoist meansfor raising, lowering, and holding a furnace load between and atpositions in said chamber, in said tank, and on said load supportingtrack, and means for retracting said load supporting track to permitraising or lowering of' a furnace load and for projecting the same toreceive and support a furnace load. 4

10. A heat treating apparatus comprising a heating chamber elevatedabove floor level, a

' quenching tank under. said chamber but depressed below floor level,said chamber and said tank being vertically separated a distance greaterthan the load height of saidchamber to provide therebetween a loadingspace at and above floor level, a load carrier track extending throughsaid loading space for movably'supporting a load carrier, a load carrieradapted to move along said load carrier track and to carry a furnaceload of metal sheets dependingly hung therefrom, a door in the bottom ofsaid heating chamber adapted to be opened and closed for the receipt anddischarge of a load carrier, hoisting means withdrawable into saidchamber and extendable into said tank, means for attaching said hoistingmeans to said load carrier, and means for retracting at least thatportion of said load carrier track which is directly under said chamberto at least one side of said chamber after engagement of said hoistingmeanswith said load carrier, said retracting means being adapted tosubsequently project said portion of said load carrier track to loadsupporting position, whereby the load carrier and its load maybewithdrawn into said chamber, lowered into said tank, and returned tosaid load carrier track by said hoisting means, and whereby said loadcarrier track provides delivery and removal means for said load carrier.

11. A heat treating apparatus comprising a heating chamber elevatedabove floor level, a

quenching tank under said chamber but depressed below floor level, saidchamber and said tank being vertically separated a distance greater thanthe load height of said chamber to provide therebetween a loading spaceat and above floor level, a load 'carriertrack extending through 'saidloading space for movably supporting a load carrier, a load carrieradapted to move along said load carrier track and to carry a furnaceload of metal sheets dependingly hung therefrom, a door in the bottom ofsaid heating chamber adapted to be opened and closed for the receipt anddischarge of a load carrier, yieldable means for releasably pressingsaid door upwardly against the bottom of said chamber and into sealingengagementv therewith, a door supporting track above said load carriertrack extending under said door and beyond one-end of said chamber,means for horizontally moving. said door when released onto said doorsupporting track to and from a position under said chamber, hoist meansfor raising, lowering, and holding a furnace load between and atpositions in said chamber, in said tank, and on said load carrier track,and means for retracting said load supporting track to permitraising orlowering of a. furnace load and for projecting the same to receive andsupport a furnace load.

12. A heat treating apparatus comprising a. heating chamber elevatedabove floor level, a quenching tank under said chamber but depressedbelow floor level,said chamber and said tank being vertically separateda distance greater than the load height of said chamber to providetherebetween a loading space at and above floor level, a load carriertrack extending through said loading space for movably supporting a loadcarrier, a return load carrier track along one side of said heatingchamber and substantially parallel to said first mentioned load carriertrack, transfer tracks. movable for alignment with either of said loadcarrier tracks at each end thereof for transferring a load carrier fromone to the other of said load carrier tracks, a load carrier adapted tomove along said load carrier track and to carry a furnace load of metalsheets dependingly hung therefrom, a door inthe bottom of said heatingchamber adapted to be opened and closed for the receipt and discharge ofa load carrier, hoisting means withdrawable into said chamber andextendable into said tank, means for attaching said hoisting means tosaid load carrier, and means for retracting at least that portion ofsaid load carrier track which is of said chamber after engagement ofsaid hoisting, means with said load carrier, said retracting means beingadapted to subsequently project said portion of said load carrier trackto load supporting position, whereby the load carrier and its load maybe withdrawn into said chamber, lowered into said tank, and returned tosaid load carrier track by said hoisting means, and whereby said loadcarrier tracks provide a circulatory load delivery and removal system.'7

13. A heat treating apparatus comprising a heating chamber elevatedabove floor level, a quenching tank under said chamber but depressedbelow floor level, said chamber and said tank being vertically separateda distance greater than the load height of said chamber to providethereing a flow of heated air through said drying receipt and dischargeof a load carrier, hoisting chamber to evaporate clinging quench waterfrom a furnace load carried by a load carrier on said transfer track, aload carrier adapted to move along said load carrier track and to carrya furnace load of metal sheets dependingly hung therefrom, a door in thebottom of said heating chamber adapted to be opened and closed for themeans withdrawable into said chamber and extendable into said tank,means for attaching said hoisting means to said load carrier, arid meansfor retracting at least that portion of said load carrier track which isdirectly under said chamber to at least one side of said chamber afterengagement of said hoisting means with said load carrier, saidretracting means being adapted to subsequently project said portion ofsaid load carrier trackto load supporting position, whereby .the loadcarrier and its load may be withdrawn into said chamber, lowered intosaid tank, and'returned to said load carrier track by said hoistingmeans, and whereby said load carrier tracks provide a circulatory loaddelivery and removal system.

directly under said chamber to at least one side 14. In a heat treatingsystem of the type described, the combination comprising an elevatedtrack structure, a plurality of carriers movable along said track andadapted for upward movement with respect thereto, a portion of saidtrack being laterally retractable for movement of a carrier below theplane of said track, a heating chamber above said portion of said track,a tank spaced below said heating chamber a distance greater than theload height thereof to permit movement -of a loaded carriertherebetween, means engageable with-said loaded carrier be neath saidchamber for raising the same into said heating chamber and for loweringthe same into said tank, means for actuating said retractable portion ofsaid track when the loaded carrier is disposed above or below the planeof said track, a bottom closure for said chamber, and means foractuating said closure for entry and discharge of said loaded carrierinto and out of said chamber.

15. In a heat treating system of the type described, the combinationcomprising an elevated track structure, a plurality of carriers movablealong said track and adapted for upward movement with respect thereto, aportion of said track A being laterally retractable for movement of acarrier below the plane of said track, a heating chamber above saidportion of said track, a tank spaced below said heating chamber adistance greater than the load height thereof to permit movement of aloaded carrier 'therebetween, means engageable with said loaded carrierbeneath said chamber for raising the same into said heating chamber andfor lowering the same into said tank, means for actuating said retractable portion of said track when the loaded carrier is disposed above orbelow the plane of said track, a bottom closure for said chamber, andmeans for actuating said closure for entry and discharge of 'said loadedcarrier into and out of said chamber, said track structure beingarranged to accommodate said plurality of carriers simultaneously at aloading station, at an unloading station, and at a. treating stationlocated at said heating chamber for movement through a path extendingfrom each of said stations to the next station.

16. A heating. treating mechanism comprising in combination, a heatingchamber disposed and aligned above a quenching tank, a track extendingbetween chargingand discharging stations at opposite ends of the heatingchamber, said track lying in a plane directly below the heating chamberand above the quenching tank, a second track in the same plane butspaced from and parallel to the first-mentioned track, at'least onecarriage adapted to be translated along said tracks, cross railsadjacent the charging and discharging stations for connecting theparallel tracks, whereby a carriage may be laterally shunted from one tothe other of the parallel tracks, means for hoisting and lowering acarriage from the track immediately below the heating chamber, a sectionof said last-mentioned track being adapted to be spread sufliciently topermit lowering a carriage through the same into the quenching tank, andsaid parallel track arrangement providing storage for a number ofcarriages.

KIRTLAND MARSH.

